Segmentation within a broadcast domain in ethernet VPN

ABSTRACT

In one embodiment, a method includes receiving a broadcast, unknown-unicast, or multicast (BUM) frame from a connected device, where the BUM frame is associated with a broadcast domain, determining a segment within the broadcast domain associated with the device, adding to the BUM frame a segment identifier that uniquely identifies the segment within the broadcast domain, and causing the BUM frame to be delivered to one or more recipient network apparatuses in a network associated with the broadcast domain, where the segment identifier added to the BUM frame is configured to be used by the one or more recipient network apparatuses to selectively forward the BUM frame to connected devices that are associated with segment identifier.

PRIORITY

This application is a continuation under 35 U.S.C. § 120 of U.S. patentapplication Ser. No. 16/438,844, filed 12 Jun. 2019.

TECHNICAL FIELD

The present disclosure relates generally to a field of datacommunications, and more particularly, to segmenting a broadcast domainin a network providing an ethernet connectivity between sites.

BACKGROUND

A computer network can include a system of hardware, software,protocols, and transmission components that collectively allow separatedevices to communicate, share data, and access resources, such assoftware applications. More specifically, a computer network is ageographically distributed collection of nodes interconnected bycommunication links and segments for transporting data betweenendpoints, such as personal computers and workstations. Many types ofnetworks are available, ranging from local area networks (LANs) and widearea networks (WANs) to overlay and software-defined networks, such assoftware-defined local area networks (SD-LANs) and software-defined widearea networks (SD-WANs), and virtual networks such as virtual LANs(VLANs) and virtual private networks (VPNs).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example EVPN network that allows segmentationswith a broadcast domain.

FIG. 2 illustrates an example format for a Border Gateway Protocol (BGP)extended community.

FIG. 3 illustrates example tables constructed at network apparatusesbased on control plane information.

FIG. 4 illustrates an example method for forwarding a BUM frame with anadded segment identifier.

FIG. 5 illustrates an example method for selectively forwarding aunicast frame based on a comparison of segment identifier of the unicastframe to the segment identifier of the destination device.

FIG. 6 illustrates an example method for selectively forwarding a BUMframe to connected devices being associated with the segment that theBUM frame is associated with.

FIG. 7 illustrates an example computer system.

DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

In particular embodiments, a network apparatus may receive a broadcast,unknown-unicast, or multicast (BUM) frame from a device connected to thenetwork apparatus. The BUM frame may be associated with a broadcastdomain. The network apparatus may determine a first segment within thebroadcast domain associated with the device. The network apparatus mayadd a first segment identifier that uniquely identifies the firstsegment within the broadcast domain to the BUM frame. The networkapparatus may cause the BUM frame to be delivered to one or morerecipient network apparatuses in a network associated with the broadcastdomain. The first segment identifier added to the BUM frame may beconfigured to be used by the one or more recipient network apparatusesto selectively forward the BUM frame to connected devices that areassociated with first segment identifier.

In particular embodiments, a network apparatus may receive a broadcast,unknown-unicast, or multicast (BUM) frame originated from a sourcenetwork apparatus. The BUM frame may be associated with a broadcastdomain. The BUM frame may comprise a segment identifier identifying asegment within the broadcast domain. The network apparatus may comparethe segment identifier of the BUM frame to one or more second segmentidentifiers of one or more devices connected to the network apparatus.The network apparatus may forward a copy of the BUM frame to any of theone or more devices if the second segment identifier associated withthat device matches the segment identifier of the BUM frame.

EXAMPLE EMBODIMENTS

A broadcast domain is a logical division of a computer network, in whichall nodes can reach each other by broadcast at the data link layer. Abroadcast domain can be within the same LAN segment or it can be bridgedto other LAN segments. In a bridged network, the broadcast domain maycorrespond to a VLAN, where a VLAN is typically represented by a singleVLAN ID (VID) and also can be represented by several VIDs where SharedVLAN Learning (SVL) is used. An Ethernet Virtual Private Network (EVPN)may connect dispersed sites using a Layer 2 virtual bridge. An EVPNconsists of customer edge (CE) devices (host, router, or switch)connected to provider edge (PE) nodes. Throughout this disclosure, adevice may refer to a CE device, and a network apparatus may refer to aPE node. An Attachment Circuit (AC) is a physical or logical circuitbetween a PE and a CE. An EVPN Instance (EVI) may be an EVPN routing andforwarding instance spanning the PE devices participating in that EVPN.An EVI is configured on the PEs on a per-customer basis. Each PE node inan EVPN network may maintain a Virtual Routing and Forwarding table forMedia Access Control (MAC) addresses (MAC-VRF). A bridge table may aninstantiation of a broadcast domain on a MAC-VRF. When a customer site(device or network) is connected to one or more PEs via a set ofEthernet links, then that set of links may be referred to as an EthernetSegment (ES). An Ethernet Segment Identifier (ESI) may be a uniquenon-zero identifier that identifies an ES. An Ethernet Tag may identifya particular broadcast domain, e.g., a VLAN. An EVI may consist of oneor more broadcast domains. In particular embodiments, an EVI may beassociated with a single broadcast domain.

EVPN may provide ethernet bridging service where any device cancommunicate with any other device within its broadcast domain. Thisdisclosure describes methods and apparatuses to achieve segmentationwithin a broadcast domain. The advantages of segmentation within abroadcast domain may be three fold: 1) may simplify provisioning wheremultiple, subnets can be configured in a single broadcast domain andthus avoiding per-broadcast domain configuration for each subnet, 2) maysuit the hardware devices that cannot support large scale broadcastdomains, and 3) may provide a path forward for segmentations not justwithin a broadcast domain but also within a VLAN.

FIG. 1 illustrates an example EVPN network 100 that allows segmentationswith a broadcast domain. Only network entities belonging to a singlebroadcast domain are presented for the sake of brevity. A plurality ofnetwork apparatuses, PE1 111, PE2 112, PE3 113, and PE4 114 areconnected to an EVPN network. Each network apparatus is connected to oneor more customer devices. CE1 121 is connected to PE1, CE2 122 and CE5125 are connected to PE2, CE3 123 is connected to PE3, and CE4 124 isconnected to PE4. Though the network apparatuses are connected to one ortwo customer devices in the example illustrated in FIG. 1 , typical PEnodes may be connected to a large number of CEs. A frame belonging tothe broadcast domain from a customer device may be bridged through thecore network to one or more destination customer devices. In thefollowing disclosure, PE1 111 is referred to as a first networkapparatus, PE2 112 is referred to as a second network apparatus, PE3 113is referred to as a third network apparatus, and PE4 114 is referred toas a fourth network apparatus. CE1 121 is referred to as a first device,CE2 122 is referred to as a second device, CE3 123 is referred to as athird device, CE4 124 is referred to as a fourth device, and CE5 125 isreferred to as a fifth device. Although this disclosure describes aparticular EVPN network, this disclosure contemplates any suitable EVPNnetwork.

In particular embodiments, devices may attach to a network apparatusthrough an Attachment Circuit (AC). A network apparatus may have one ormore ports that are associated with ACs. Each port may be configuredwith a particular segment identifier. When a device is connected to anetwork apparatus through an AC, the network apparatus may determine thesegment identifier associated with the device based on the port that theAC is connected to. As an example and not by way of limitation,illustrated in FIG. 1 , the first device 121 is connected to the firstnetwork apparatus 111 through AC1 131. The segment identifier associatedwith the first device is 10. The second device 122 is connected to thesecond network apparatus 112 through AC2 132. The segment identifierassociated with the second device is 10. The third device 123 isconnected to the third network apparatus 113 through AC3 133. Thesegment identifier associated with the third device is 20. The fourthdevice 124 is connected to the fourth network apparatus 114 through AC4134. The segment identifier associated with the fourth device is 20. Thefifth device 125 is connected to the second network apparatus 112through AC5 135. The segment identifier associated with the fifth deviceis 30. Although this disclosure describes associating a segmentidentifier to a device in a particular manner, this disclosurecontemplates associating a segment identifier to a device in anysuitable manner.

FIG. 2 illustrates an example format for a Border Gateway Protocol (BGP)extended community. The new extended community may have a Type fieldvalue of 0x06 (EVPN). Accordingly, a new Sub-Type should be defined. Thelast bit of the Flags field may be used as a Leaf-indication, where ‘1’means leaf. In particular embodiments, all ACs may be considered as“root.” In such cases, only a single label per segment identifier may beneeded. In particular embodiments, an AC may need to be either “root” or“leaf” in an Ethernet-Tree (E-TREE). Then, two MPLS labels per segmentidentifier may be needed. A segment identifier may be a 16-bit integer.In particular embodiments, a single broadcast domain may comprise aplurality of VLANs. In such cases, a 12-bit VID may be used as a segmentidentifier. Each advertising network apparatus may allocate one or twoMILS labels for a given segment. These labels may be advertised in theleaf/root label field. When a network apparatus advertises two extendedcommunities for a segment, one may be for <root, segment> and anotherfor <leaf, segment>. In particular embodiments, the extended communitymay be advertised along with the EAD-ES route (with an ESI of zero) forBUM traffic to enable egress filtering on disposition networkapparatuses. In particular embodiments, the extended community may beadvertised along with the MAC/IP advertisement route for known unicasttraffic. On receiving the advertisements, the receiving networkapparatus may store these labels to be used when sending BUM traffic tothat network apparatus. If a BUM frame arrives on a root AC, then the“root” label may be used. If the BUM frame arrives on a “leaf AC”, thenthe “leaf” label may be used. The root or leaf label for the determinedsegment may be added to BUM frames. Although this disclosure describesadvertising control plane information associated with a segment in aparticular manner, this disclosure contemplates advertising controlplane information associated with a segment in any suitable manner.

Referring again to FIG. 1 , in particular embodiments, a first networkapparatus 111 in a network may receive a BUM frame from a first device121 connected to the first network apparatus 111. The BUM frame may beassociated with a broadcast domain. The network may provide ethernetconnectivity between sites spanning metropolitan area networks and widearea networks. In particular embodiments, the network may be an EVPN. Inparticular embodiments, the network may be an EVPN. As an example andnot by way of limitation, the first device 121 may send an addressresolution protocol (ARP) request message to determine a MAC addressassociated with an Internet Protocol (IP) address. An ARP request is abroadcast message. The first network apparatus 111 may receive the ARPmessage from the first device 121. Although this disclosure describesreceiving a BUM frame from a device in a particular manner, thisdisclosure contemplates receiving a BUM frame from a device in anysuitable manner.

In particular embodiments, the broadcast domain may be identified basedon a VLAN identifier (VID) associated with the BUM frame. In particularembodiments, virtual local area network bundle service for EVPN may beutilized. In such cases, the broadcast domain is identified based on anEVPN Instance (EVI) identifier associated with the BUM frame. Althoughthis disclosure describes identifying a broadcast domain associated witha BUM frame in a particular manner, this disclosure contemplatesidentifying a broadcast domain associated with a BUM frame in anysuitable manner.

In particular embodiments, the first network apparatus 111 may determinea first segment within the broadcast domain associated with the firstdevice 121. The determination of the first segment may be based on aport through which the first device 121 connects to the networkapparatus. As an example and not by way of limitation, continuing with aprior example, the first device 121 connects to the first networkapparatus through AC1. The port associated with AC1 is configured withsegment identifier 10. Thus, the first network apparatus 111 determinesthat the first device 122 is associated with the segment identifier 10.Although this disclosure describes determining a segment identifierassociated with a device sending a BUM frame in a particular manner,this disclosure contemplates determining a segment identifier associatedwith a device sending a BUM frame in any suitable manner.

In particular embodiments, the first network apparatus 111 may add afirst segment identifier that uniquely identifies the first segmentwithin the broadcast domain to the BUM frame. After the addition of thefirst segment identifier to the BUM frame, the BUM frame may comprise alabel comprising information associated with the first segmentidentifier. In particular embodiments, root/leaf distinction within asegment may not be needed. In such cases, a single downstream assignedMPLS label may be used for each segment identifier. In particularembodiments, a segment may be associated with both root and leaf sites.In such cases, two downstream assigned MPLS label may be used for eachsegment identifier: one for root and another for leaf. As an example andnot by way of limitation, continuing with a prior example, the firstnetwork apparatus 111 may add a label comprising information associatedwith the segment identifier 10 to the BUM frame. Although thisdisclosure describes adding a segment identifier to a BUM frame in aparticular manner, this disclosure contemplates adding a segmentidentifier to a BUM frame in any suitable manner.

In particular embodiments, the first network apparatus 111 may cause theBUM frame to be delivered to one or more recipient network apparatusesin the network associated with the broadcast domain. The first networkapparatus 111 may add routing information to the BUM frame. Inparticular embodiments, the routing information may comprise one or moreMPLS labels. The one or more MPLS labels may comprise instructions forrouting the BUM frame to the one or more recipient network apparatus inthe broadcast domain through the EVPN network. The first segmentidentifier added to the BUM frame is configured to be used by the one ormore recipient network apparatuses to selectively forward the BUM frameto connected devices that are with associated with the first segmentidentifier. As an example and not by way of limitation, illustrated inFIG. 1 , continuing with a prior example, the first network apparatus111 may forward the BUM frame through the EVPN network. The network maydeliver the BUM frame to the second network apparatus, the third networkapparatus and the fourth network apparatus because those networkapparatuses are associated with the broadcast domain. Although thisdisclosure describes causing a BUM frame to be delivered to one or morerecipient network apparatuses in a particular manner, this disclosurecontemplates this happening in any suitable manner.

In particular embodiments, a second network apparatus 112 may receive aBUM frame originated from the first network apparatus 111. The BUM framemay comprise a broadcast domain identifier identifying the broadcastdomain associated with the BUM frame and a segment identifieridentifying a segment within the broadcast domain. The segmentidentifier may be acquired based on a label of the BUM frame. The labelmay be attached to the BUM frame, which is an ethernet frame. As anexample and not by way of limitation, continuing with a prior example,the ARP request from the first device 121 is delivered to the secondnetwork apparatus 112. The second network apparatus 112 may determinethe broadcast domain associated with the ARP request message based onthe VID on the frame. The second network apparatus 112 may determine thesegment associated with the ARP request message based on the segmentidentifier acquired from the label attached to the ARP request message.Although this disclosure describes determining a broadcast domain and asegment associated with a BUM frame upon receiving the BUM frame in aparticular manner, this disclosure contemplates determining a broadcastdomain and a segment associated with a BUM frame upon receiving the BUMframe in any suitable manner.

In particular embodiments, the second network apparatus 112 may comparethe broadcast domain identifier of the BUM frame to one or morebroadcast domain identifiers of one or more devices connected to thesecond network apparatus 112. As an example and not by way oflimitation, illustrated in FIG. 1 , the devices illustrated in FIG. 1belong to a single broadcast domain for the sake of brevity. Thus, thesecond network apparatus 112 may determine that both the second device122 and the fifth device 125 belong to the broadcast domain associatedwith the ARP request message. Although this disclosure describescomparing the broadcast domain identifier associated with a received BUMframe and the broadcast domain identifiers associated with connecteddevices in a particular manner, this disclosure contemplates comparingthe broadcast domain identifier associated with a received BUM frame andthe broadcast domain identifiers associated with connected devices inany suitable manner.

In particular embodiments, the second network apparatus 112 may comparethe segment identifier of the BUM frame to one or more second segmentidentifiers of the one or more devices associated with the broadcastdomain. As an example and not by way of limitation, continuing with aprior example, the second network apparatus 112 may compare the segmentidentifier 10 associated with the ARP request message with the segmentidentifier 10 associated with the second device 122 and the segmentidentifier 30 associated with the fifth device 125. The second networkapparatus 112 may determine that only the segment identifier associatedwith the second device 122 matches the segment identifier associatedwith the ARP request message. As another example and not by way oflimitation, the third network apparatus 113 may compare the segmentidentifier associated with the received ARP request message sent by thefirst device 121 with the segment identifier associated with the thirddevice 123. The third network apparatus 113 may determine that noconnected device is associated with the segment identifier associatedwith the ARP request message. As yet another example and not by way oflimitation, the fourth network apparatus 114 may compare the segmentidentifier associated with the received ARP request message sent by thefirst device 121 with the segment identifier associated with the fourthdevice 124. The fourth network apparatus 114 may determine that noconnected device is associated with the segment identifier associatedwith the ARP request message. Although this disclosure describescomparing the segment identifier associated with the received BUM framewith segment identifiers associated with connected devices in aparticular manner, this disclosure contemplates comparing the segmentidentifier associated with the received BUM frame with segmentidentifiers associated with connected devices in any suitable manner.

In particular embodiments, the second network apparatus 112 may forwarda copy of the BUM frame to any of the one or more devices if the secondsegment identifier associated with that device matches the segmentidentifier of the BUM frame. The second network apparatus 112 may removethe label from the BUM frame before forwarding the copy of the BUMframe. As an example and not by way of limitation, continuing with aprior example, the second network apparatus 112 takes an ethernet framefor the ARP request message by removing the label from the frame. Thesecond network apparatus 112 forwards a copy of the ARP request messageto the second device 122 because the segment identifier associated withthe second device 122 matches the segment identifier associated with theARP request message. However, the second network apparatus 112 does notforward the ARP request to the fifth device 125 because the segmentidentifier associated with the fifth device 125 does not match thesegment identifier associated with the ARP request message. Althoughthis disclosure describes forwarding a copy of a BUM frame to a deviceif the segment identifier associated with the device matches the segmentidentifier associated with the BUM frame in a particular manner, thisdisclosure contemplates forwarding a copy of a BUM frame to a device ifthe segment identifier associated with the device matches the segmentidentifier associated with the BUM frame in any suitable manner.

In particular embodiments, the third network apparatus 113 may discardthe received BUM frame if no second segment identifier associated withone or more devices associated with the broadcast domain matches thesegment identifier of the BUM frame. As an example and not by way oflimitation, continuing with a prior example, the third network apparatus113 does not forward the received ARP request to the third device 123because the segment identifier associated with the third device 123 doesnot match the segment identifier associated with the ARP requestmessage. The third network apparatus 113 discards the received ARPmessage. As another example and not by way of limitation, continuingwith a prior example, the fourth network apparatus 114 does not forwardthe received ARP request to the fourth device 124 because the segmentidentifier associated with the fourth device 124 does not match thesegment identifier associated with the ARP request message. The fourthnetwork apparatus 114 discards the received ARP message. Although thisdisclosure describes discarding a received BUM frame in a particularmanner if no connected device is associated with the segment identifierassociated with the BUM frame, this disclosure contemplates discarding areceived BUM frame in any suitable manner if no connected device isassociated with the segment identifier associated with the BUM frame.

In particular embodiments, the first network apparatus 111 may advertisecontrol plane information associated with the first network apparatus111. The control plane information may be carried over BGP messages. Thecontrol plane information may comprise one or two extended communitiesper segment. On receiving the advertisements, the second networkapparatus 112 may store the received control plane information. MACaddresses of devices should be unique across all segments for a givencustomer. FIG. 3 illustrates example tables constructed at networkapparatuses based on control plane information. The tables illustratedin FIG. 3 are simplified for presentation purpose. In the exampleillustrated in FIG. 3 , M1 is a MAC address associated with the firstdevice 121. M2 is a MAC address associated with the second device 122.M3 is a MAC address associated with the third device 123. M4 is a MACaddress associated with the fourth device 124. M5 is a MAC addressassociated with the fifth device 125. Although this disclosure describesexchanging control plane information between network apparatuses in aparticular manner, this disclosure contemplates exchanging control planeinformation between network apparatuses in any suitable manner.

In particular embodiments, the first network apparatus 111 may receive aunicast frame from the first device 121 connected to the first networkapparatus 111. The unicast frame is intended for a destination device inthe broadcast domain. As an example and not by way of limitation, thefirst device 121 may send a unicast ethernet frame to the fifth device125. The first network apparatus 111 may receive the unicast frame sentto the fifth device 125 from the first device 121. Although thisdisclosure describes receiving a unicast ethernet frame from a connecteddevice in a particular manner, this disclosure contemplates receiving aunicast ethernet frame from a connected device in any suitable manner.

In particular embodiments, the first network apparatus 111 may determinethat the first segment is associated with the unicast frame. Thedetermination of the first segment may be based on a port through whichthe first device 121 connects to the first network apparatus 111. As anexample and not by way of limitation, continuing with a prior example,the first network apparatus 111 determines that the unicast frame isassociated with a first segment identifier “10” based on the port towhich AC1 131 is connected. Although this disclosure describesdetermining a segment associated with a unicast frame in a particularmanner, this disclosure contemplates determining a segment associatedwith a unicast frame in any suitable manner.

In particular embodiments, the first network apparatus 111 mayselectively determine whether to forward the unicast frame towards thedestination device based on a comparison between the first segmentidentifier associated with the first segment and a second segmentidentifier associated with the destination device. Informationassociated with the second segment identifier being associated with thedestination device may be obtained from control plane informationreceived through the network associated with the broadcast domain. Thecontrol plane information may be carried over BGP messages. As anexample and not by way of limitation, continuing with a prior example,the first network apparatus 111 compares the first segment identifier“10” associated with the unicast frame and a second segment identifier“30” associated with the fifth device 125, the destination of theunicast frame. The first network apparatus 111 may determine that thefirst segment identifier does not match the second segment identifier.Although this disclosure describes determining whether to forward aunicast frame based on a comparison between a segment identifierassociated with a unicast frame and a segment identifier associated witha destination device in a particular manner, this disclosurecontemplates determining whether to forward a unicast frame based on acomparison between a segment identifier associated with a unicast frameand a segment identifier associated with a destination device in anysuitable manner.

In particular embodiments, the first network apparatus 111 may discardthe unicast frame without forwarding the unicast frame toward thedestination device if the first segment identifier and the secondsegment identifier are different. As an example and not by way oflimitation, continuing with a prior example, the first network apparatusdiscards the unicast frame received from the first device 121 withoutforwarding the unicast frame to the fifth device 125, the destination ofthe unicast frame, because the segment identifier associated with theunicast frame does not match the segment identifier associated with thedestination device. Although this disclosure describes discarding aunicast frame in a particular manner, this disclosure contemplatesdiscarding a unicast frame in any suitable manner.

FIG. 4 illustrates an example method 400 for forwarding a BUM frame withan added segment identifier. The method may begin at step 410, where anetwork apparatus may receive a BUM frame from a device connected to thenetwork apparatus. The BUM frame may be associated with a broadcastdomain. At step 420, the network apparatus may determine a first segmentwithin the broadcast domain associated with the device. At step 430, thenetwork apparatus may add to the BUM frame a first segment identifierthat uniquely identifies the first segment within the broadcast domain.At step 440, the network apparatus may cause the BUM frame to bedelivered to one or more recipient network apparatuses in a networkassociated with the broadcast domain. The first segment identifier addedto the BUM frame may be configured to be used by the one or morerecipient network apparatuses to selectively forward the BUM frame toconnected devices that are with associated with first segmentidentifier. Particular embodiments may repeat one or more steps of themethod of FIG. 4 , where appropriate. Although this disclosure describesand illustrates particular steps of the method of FIG. 4 as occurring ina particular order, this disclosure contemplates any suitable steps ofthe method of FIG. 4 occurring in any suitable order. Moreover, althoughthis disclosure describes and illustrates an example method forforwarding a BUM frame with an added segment identifier including theparticular steps of the method of FIG. 4 , this disclosure contemplatesany suitable method for forwarding a BUM frame with an added segmentidentifier including any suitable steps, which may include all, some, ornone of the steps of the method of FIG. 4 , where appropriate.Furthermore, although this disclosure describes and illustratesparticular components, devices, or systems carrying out particular stepsof the method of FIG. 4 , this disclosure contemplates any suitablecombination of any suitable components, devices, or systems carrying outany suitable steps of the method of FIG. 4 .

FIG. 5 illustrates an example method 500 for selectively forwarding aunicast frame based on a comparison of segment identifier of the unicastframe to the segment identifier of the destination device. The methodmay begin at step 510, where a network apparatus may receive a unicastframe from the device connected to the network apparatus. The unicastframe may be intended for a destination device in the broadcast domain.At step 520, the network apparatus may determine that the first segmentis associated with the unicast frame. At step 530, the network apparatusmay determine that the second segment is associated with the destinationdevice. At step 540, the network apparatus may compare the first segmentidentifier associated with the first segment with the second segmentidentifier associated with the destination device. At step 550, thenetwork apparatus may forward the unicast frame towards the destinationdevice if the second segment identifier matches the first segmentidentifier. At step 560, the network apparatus may discard the unicastframe without forwarding the unicast frame to the destination if thesecond segment identifier does not match the first segment identifier.Particular embodiments may repeat one or more steps of the method ofFIG. 5 , where appropriate. Although this disclosure describes andillustrates particular steps of the method of FIG. 5 as occurring in aparticular order, this disclosure contemplates any suitable steps of themethod of FIG. 5 occurring in any suitable order. Moreover, althoughthis disclosure describes and illustrates an example method forselectively forwarding a unicast frame based on a comparison of segmentidentifier of the unicast frame to the segment identifier of thedestination device including the particular steps of the method of FIG.5 , this disclosure contemplates any suitable method for selectivelyforwarding a unicast frame based on a comparison of segment identifierof the unicast frame to the segment identifier of the destination deviceincluding any suitable steps, which may include all, some, or none ofthe steps of the method of FIG. 5 , where appropriate. Furthermore,although this disclosure describes and illustrates particularcomponents, devices, or systems carrying out particular steps of themethod of FIG. 5 , this disclosure contemplates any suitable combinationof any suitable components, devices, or systems carrying out anysuitable steps of the method of FIG. 5 .

FIG. 6 illustrates an example method 600 for selectively forwarding aBUM frame to connected devices being associated with the segment thatthe BUM frame is associated with. The method may begin at step 610,where a network apparatus may receive a BUM frame originated from asource network apparatus. The BUM frame may be associated with abroadcast domain. The BUM frame may comprise a segment identifieridentifying a segment within the broadcast domain. At step 620, thenetwork apparatus may, for each device connected to the network device,compare the segment identifier of the BUM frame to a second segmentidentifier of the device. At step 630, the network apparatus may forwarda copy of the BUM frame to the devices if the second segment identifierassociated with that device matches the segment identifier of the BUMframe. At step 640, the network apparatus may not forward a copy of theBUM frame to the devices if the second segment identifier associatedwith that device matches the segment identifier of the BUM frame.Particular embodiments may repeat one or more steps of the method ofFIG. 6 , where appropriate. Although this disclosure describes andillustrates particular steps of the method of FIG. 6 as occurring in aparticular order, this disclosure contemplates any suitable steps of themethod of FIG. 6 occurring in any suitable order. Moreover, althoughthis disclosure describes and illustrates an example method forselectively forwarding a BUM frame to connected devices being associatedwith the segment that the BUM frame is associated with including theparticular steps of the method of FIG. 6 , this disclosure contemplatesany suitable method for selectively forwarding a BUM frame to connecteddevices being associated with the segment that the BUM frame isassociated with including any suitable steps, which may include all,some, or none of the steps of the method of FIG. 6 , where appropriate.Furthermore, although this disclosure describes and illustratesparticular components, devices, or systems carrying out particular stepsof the method of FIG. 6 , this disclosure contemplates any suitablecombination of any suitable components, devices, or systems carrying outany suitable steps of the method of FIG. 6 .

FIG. 7 illustrates an example computer system 700. In particularembodiments, one or more computer systems 700 perform one or more stepsof one or more methods described or illustrated herein. In particularembodiments, one or more computer systems 700 provide functionalitydescribed or illustrated herein. In particular embodiments, softwarerunning on one or more computer systems 700 performs one or more stepsof one or more methods described or illustrated herein or providesfunctionality described or illustrated herein. Particular embodimentsinclude one or more portions of one or more computer systems 700.Herein, reference to a computer system may encompass a computing device,and vice versa, where appropriate. Moreover, reference to a computersystem may encompass one or more computer systems, where appropriate.

This disclosure contemplates any suitable number of computer systems700. This disclosure contemplates computer system 700 taking anysuitable physical form. As example and not by way of limitation,computer system 700 may be an embedded computer system, a system-on-chip(SOC), a single-board computer system (SBC) (such as, for example, acomputer-on-module (COM) or system-on-module (SOM)), a desktop computersystem, a laptop or notebook computer system, an interactive kiosk, amainframe, a mesh of computer systems, a mobile telephone, a personaldigital assistant (PDA), a server, a tablet computer system, anaugmented/virtual reality device, or a combination of two or more ofthese. Where appropriate, computer system 700 may include one or morecomputer systems 700; be unitary or distributed; span multiplelocations; span multiple machines; span multiple data centers; or residein a cloud, which may include one or more cloud components in one ormore networks. Where appropriate, one or more computer systems 700 mayperform without substantial spatial or temporal limitation one or moresteps of one or more methods described or illustrated herein. As anexample and not by way of limitation, one or more computer systems 700may perform in real time or in batch mode one or more steps of one ormore methods described or illustrated herein. One or more computersystems 700 may perform at different times or at different locations oneor more steps of one or more methods described or illustrated herein,where appropriate.

In particular embodiments, computer system 700 includes a processor 702,memory 704, storage 706, an input/output (I/O) interface 708, acommunication interface 710, and a bus 712. Although this disclosuredescribes and illustrates a particular computer system having aparticular number of particular components in a particular arrangement,this disclosure contemplates any suitable computer system having anysuitable number of any suitable components in any suitable arrangement.

In particular embodiments, processor 702 includes hardware for executinginstructions, such as those making up a computer program. As an exampleand not by way of limitation, to execute instructions, processor 702 mayretrieve (or fetch) the instructions from an internal register, aninternal cache, memory 704, or storage 706; decode and execute them; andthen write one or more results to an internal register, an internalcache, memory 704, or storage 706. In particular embodiments, processor702 may include one or more internal caches for data, instructions, oraddresses. This disclosure contemplates processor 702 including anysuitable number of any suitable internal caches, where appropriate. Asan example and not by way of limitation, processor 702 may include oneor more instruction caches, one or more data caches, and one or moretranslation lookaside buffers (TLBs). Instructions in the instructioncaches may be copies of instructions in memory 704 or storage 706, andthe instruction caches may speed up retrieval of those instructions byprocessor 702. Data in the data caches may be copies of data in memory704 or storage 706 for instructions executing at processor 702 tooperate on; the results of previous instructions executed at processor702 for access by subsequent instructions executing at processor 702 orfor writing to memory 704 or storage 706; or other suitable data. Thedata caches may speed up read or write operations by processor 702. TheTLBs may speed up virtual-address translation for processor 702. Inparticular embodiments, processor 702 may include one or more internalregisters for data, instructions, or addresses. This disclosurecontemplates processor 702 including any suitable number of any suitableinternal registers, where appropriate. Where appropriate, processor 702may include one or more arithmetic logic units (ALUs); be a multi-coreprocessor; or include one or more processors 702. Although thisdisclosure describes and illustrates a particular processor, thisdisclosure contemplates any suitable processor.

In particular embodiments, memory 704 includes main memory for storinginstructions for processor 702 to execute or data for processor 702 tooperate on. As an example and not by way of limitation, computer system700 may load instructions from storage 706 or another source (such as,for example, another computer system 700) to memory 704. Processor 702may then load the instructions from memory 704 to an internal registeror internal cache. To execute the instructions, processor 702 mayretrieve the instructions from the internal register or internal cacheand decode them. During or after execution of the instructions,processor 702 may write one or more results (which may be intermediateor final results) to the internal register or internal cache. Processor702 may then write one or more of those results to memory 704. Inparticular embodiments, processor 702 executes only instructions in oneor more internal registers or internal caches or in memory 704 (asopposed to storage 706 or elsewhere) and operates only on data in one ormore internal registers or internal caches or in memory 704 (as opposedto storage 706 or elsewhere). One or more memory buses (which may eachinclude an address bus and a data bus) may couple processor 702 tomemory 704. Bus 712 may include one or more memory buses, as describedbelow. In particular embodiments, one or more memory management units(MMUs) reside between processor 702 and memory 704 and facilitateaccesses to memory 704 requested by processor 702. In particularembodiments, memory 704 includes random access memory (RAM). This RAMmay be volatile memory, where appropriate. Where appropriate, this RAMmay be dynamic RAM (DRAM) or static RAM (SRAM). Moreover, whereappropriate, this RAM may be single-ported or multi-ported RAM. Thisdisclosure contemplates any suitable RAM. Memory 704 may include one ormore memories 704, where appropriate. Although this disclosure describesand illustrates particular memory, this disclosure contemplates anysuitable memory.

In particular embodiments, storage 706 includes mass storage for data orinstructions. As an example and not by way of limitation, storage 706may include a hard disk drive (HDD), a floppy disk drive, flash memory,an optical disc, a magneto-optical disc, magnetic tape, or a UniversalSerial Bus (USB) drive or a combination of two or more of these. Storage706 may include removable or non-removable (or fixed) media, whereappropriate. Storage 706 may be internal or external to computer system700, where appropriate. In particular embodiments, storage 706 isnon-volatile, solid-state memory. In particular embodiments, storage 706includes read-only memory (ROM). Where appropriate, this ROM may bemask-programmed ROM, programmable ROM (PROM), erasable PROM (EPROM),electrically erasable PROM (EEPROM), electrically alterable ROM (EAROM),or flash memory or a combination of two or more of these. Thisdisclosure contemplates mass storage 706 taking any suitable physicalform. Storage 706 may include one or more storage control unitsfacilitating communication between processor 702 and storage 706, whereappropriate. Where appropriate, storage 706 may include one or morestorages 706. Although this disclosure describes and illustratesparticular storage, this disclosure contemplates any suitable storage.

In particular embodiments, I/O interface 708 includes hardware,software, or both, providing one or more interfaces for communicationbetween computer system 700 and one or more I/O devices. Computer system700 may include one or more of these I/O devices, where appropriate. Oneor more of these I/O devices may enable communication between a personand computer system 700. As an example and not by way of limitation, anI/O device may include a keyboard, keypad, microphone, monitor, mouse,printer, scanner, speaker, still camera, stylus, tablet, touch screen,trackball, video camera, another suitable I/O device or a combination oftwo or more of these. An I/O device may include one or more sensors.This disclosure contemplates any suitable I/O devices and any suitableI/O interfaces 708 for them. Where appropriate, I/O interface 708 mayinclude one or more device or software drivers enabling processor 702 todrive one or more of these I/O devices. I/O interface 708 may includeone or more I/O interfaces 708, where appropriate. Although thisdisclosure describes and illustrates a particular I/O interface, thisdisclosure contemplates any suitable I/O interface.

In particular embodiments, communication interface 710 includeshardware, software, or both providing one or more interfaces forcommunication (such as, for example, packet-based communication) betweencomputer system 700 and one or more other computer systems 700 or one ormore networks. As an example and not by way of limitation, communicationinterface 710 may include a network interface controller (NIC) ornetwork adapter for communicating with an Ethernet or other wire-basednetwork or a wireless NIC (WNIC) or wireless adapter for communicatingwith a wireless network, such as a WI-FI network. This disclosurecontemplates any suitable network and any suitable communicationinterface 710 for it. As an example and not by way of limitation,computer system 700 may communicate with an ad hoc network, a personalarea network (PAN), a local area network (LAN), a wide area network(WAN), a metropolitan area network (MAN), or one or more portions of theInternet or a combination of two or more of these. One or more portionsof one or more of these networks may be wired or wireless. As anexample, computer system 700 may communicate with a wireless PAN (WPAN)(such as, for example, a BLUETOOTH WPAN), a WI-FI network, a WI-MAXnetwork, a cellular telephone network (such as, for example, a GlobalSystem for Mobile Communications (GSM) network, a Long-Term Evolution(LTE) network, or a 5G network), or other suitable wireless network or acombination of two or more of these. Computer system 700 may include anysuitable communication interface 710 for any of these networks, whereappropriate. Communication interface 710 may include one or morecommunication interfaces 710, where appropriate. Although thisdisclosure describes and illustrates a particular communicationinterface, this disclosure contemplates any suitable communicationinterface.

In particular embodiments, bus 712 includes hardware, software, or bothcoupling components of computer system 700 to each other. As an exampleand not by way of limitation, bus 712 may include an AcceleratedGraphics Port (AGP) or other graphics bus, an Enhanced Industry StandardArchitecture (EISA) bus, a front-side bus (FSB), a HYPERTRANSPORT (HT)interconnect, an Industry Standard Architecture (ISA) bus, an INFINIBANDinterconnect, a low-pin-count (LPC) bus, a memory bus, a Micro ChannelArchitecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, aPCI-Express (PCIe) bus, a serial advanced technology attachment (SATA)bus, a Video Electronics Standards Association local (VLB) bus, oranother suitable bus or a combination of two or more of these. Bus 712may include one or more buses 712, where appropriate. Although thisdisclosure describes and illustrates a particular bus, this disclosurecontemplates any suitable bus or interconnect.

Herein, a computer-readable non-transitory storage medium or media mayinclude one or more semiconductor-based or other integrated circuits(ICs) (such, as for example, field-programmable gate arrays (FPGAs) orapplication-specific ICs (ASICs)), hard disk drives (HDDs), hybrid harddrives (HHDs), optical discs, optical disc drives (ODDs),magneto-optical discs, magneto-optical drives, floppy diskettes, floppydisk drives (FDDs), magnetic tapes, solid-state drives (SSDs),RAM-drives, SECURE DIGITAL cards or drives, any other suitablecomputer-readable non-transitory storage media, or any suitablecombination of two or more of these, where appropriate. Acomputer-readable non-transitory storage medium may be volatile,non-volatile, or a combination of volatile and non-volatile, whereappropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

The scope of this disclosure encompasses all changes, substitutions,variations, alterations, and modifications to the example embodimentsdescribed or illustrated herein that a person having ordinary skill inthe art would comprehend. The scope of this disclosure is not limited tothe example embodiments described or illustrated herein. Moreover,although this disclosure describes and illustrates respectiveembodiments herein as including particular components, elements,feature, functions, operations, or steps, any of these embodiments mayinclude any combination or permutation of any of the components,elements, features, functions, operations, or steps described orillustrated anywhere herein that a person having ordinary skill in theart would comprehend. Furthermore, reference in the appended claims toan apparatus or system or a component of an apparatus or system beingadapted to, arranged to, capable of, configured to, enabled to, operableto, or operative to perform a particular function encompasses thatapparatus, system, component, whether or not it or that particularfunction is activated, turned on, or unlocked, as long as thatapparatus, system, or component is so adapted, arranged, capable,configured, enabled, operable, or operative. Additionally, although thisdisclosure describes or illustrates particular embodiments as providingparticular advantages, particular embodiments may provide none, some, orall of these advantages.

What is claimed is:
 1. A network apparatus, comprising: one or moreprocessors; and one or more computer-readable non-transitory storagemedia coupled to the one or more processors and comprising instructionsoperable when executed by the one or more processors to cause thenetwork apparatus to: receive a first control plane informationindicating a first device is associated with a first segment within abroadcast domain, wherein the first control plane information isreceived through a network associated with a broadcast domain; store arecord of an association between the first device and the first segmentwithin the broadcast domain; receive, from a second device connected tothe network apparatus, a unicast frame destined to the first device,wherein the unicast frame is determined to be associated with a secondsegment within the broadcast domain based on a port through which thesecond device connects to the network apparatus; determine that thesecond segment is identical to the first segment by looking up thestored record; and cause, in response to the determination, the unicastframe to be delivered to the first device through the network associatedwith the broadcast domain.
 2. The network apparatus of claim 1, the oneor more processors are further operable when executing the instructionsto: send a second control plane information indicating that the seconddevice is associated with the second segment.
 3. The network apparatusof claim 1, wherein the first control plane information is carried overBorder Gateway Protocol (BGP) messages.
 4. The network apparatus ofclaim 1, wherein the network is an Ethernet Virtual Private Network(EVPN).
 5. The network apparatus of claim 4, wherein the networkapparatus is a provider edge (PE) node of the EVPN.
 6. The networkapparatus of claim 4, wherein the first device and the second device arecustomer edge (CE) devices of the EVPN.
 7. The network apparatus ofclaim 4, wherein the first control plane information is advertised alongwith an Ethernet Auto Discovery Route per Ethernet Segment (EAD-ESroute).
 8. The network apparatus of claim 4, wherein the first controlplane information is advertised along with a Media Access Control(MAC)/Internet Protocol (IP) advertisement route.
 9. The networkapparatus of claim 4, wherein the broadcast domain is identified basedon an EVPN Instance (EVI) identifier associated with the unicast frame.10. The network apparatus of claim 1, wherein the record is stored to abridge table associated with the broadcast domain.
 11. The networkapparatus of claim 1, wherein the broadcast domain is associated with aplurality of virtual local area network (VLAN) identifiers.
 12. Thenetwork apparatus of claim 11, wherein shared VLAN learning (SVL) isused for the broadcast domain.
 13. A method comprising, by a networkapparatus: receiving a first control plane information indicating afirst device is associated with a first segment within a broadcastdomain, wherein the first control plane information is received througha network associated with a broadcast domain; storing a record of anassociation between the first device and the first segment within thebroadcast domain; receiving, from a second device connected to thenetwork apparatus, a unicast frame destined to the first device, whereinthe unicast frame is determined to be associated with a second segmentwithin the broadcast domain based on a port through which the seconddevice connects to the network apparatus; determining that the secondsegment is identical to the first segment by looking up the storedrecord; and causing, in response to the determination, the unicast frameto be delivered to the first device through the network associated withthe broadcast domain.
 14. The method of claim 13, further comprising:sending a second control plane information indicating that the seconddevice is associated with the second segment.
 15. The method of claim13, wherein the first control plane information is carried over BorderGateway Protocol (BGP) messages.
 16. The method of claim 13, wherein thenetwork is an Ethernet Virtual Private Network (EVPN).
 17. The method ofclaim 16, wherein the network apparatus is a provider edge (PE) node ofthe EVPN.
 18. The method of claim 16, wherein the first device and thesecond device are customer edge (CE) devices of the EVPN.
 19. The methodof claim 16, wherein the first control plane information is advertisedalong with an Ethernet Auto Discovery Route per Ethernet Segment (EAD-ESroute).
 20. One or more computer-readable non-transitory storage mediaembodying software that is operable when executed, by a networkapparatus, to: receive a first control plane information indicating afirst device is associated with a first segment within a broadcastdomain, wherein the first control plane information is received througha network associated with a broadcast domain; store a record of anassociation between the first device and the first segment within thebroadcast domain; receive, from a second device connected to the networkapparatus, a unicast frame destined to the first device, wherein theunicast frame is determined to be associated with a second segmentwithin the broadcast domain based on a port through which the seconddevice connects to the network apparatus; determine that the secondsegment is identical to the first segment by looking up the storedrecord; and cause, in response to the determination, the unicast frameto be delivered to the first device through the network associated withthe broadcast domain.